Method of making a heat exchanger



Nov. 8, 1955 R. A. SANDBERG 2,722,732

METHOD OF MAKING A HEAT EXCHANGER Filed April 19. 1949 3 Sheets-Sheet lWK7N "IIMMHNAlwin .1* mulmlmw "hwmlmil'm 000800000808000800000000 1 nhymn wl hnl'ml" M' Y "1mWlunllW'nm""n uw '1mm "www mm W7mmmm-ummwu|.Mwnnw 'mm 0 0 0 0 0 0 0 0 0 0 0000000 Early QH. Sandberg Nov. 8, 1955R. A. SANDBERG METHOD OFI MAKING A HEAT EXCHANGER 3 Sheets-Sheet 2 FiledApril 19. 1949 fmVEnZ'ar' EatycH.5az2db-exg HLLHE Nov. 8, 1955 R. A.sANDBl-:RG

METHOD OF' MAKING A HEAT EXCHANGER 3 Sheets-Sheet 5 Filed April 19. 1949.ELLES fn VEEL Unite States Patent O METHOD or MAKING A HEAT EXCHANGERRay A. Sandberg, Waukegan, Ill., assigner to Houdaille- HersheyCorporation, Detroit, Mich., a corporation of Michigan Application April19, 1949, Serial No. 88,342

1 Claim. (Cl. 29157.3)

The present invention relates to a radiant heat panel and to methods formaking the same. More particularly, the present invention relates to aradiant heat panel con struction capable of serving as a plaster baseand as a heat exchanger and to methods for making such a radiant heatpanel.

The use of metal plaster laths, both in the form of perforated metalsheets and as an expanded metal sheet, is old in the housing art. Also,use of radiant heat panels for heating has also been proposed. Suchpanels have been employed as base boards or embedded in the walls,floors or ceilings of rooms to replace the more conventional radiator orhot air heating systems.

The present invention now provides an improved radiant heat panelconstruction capable of serving both as a plaster base to replaceconventional sheet metal lath, and as a heat exchanger to replace thattype of radiant panel previously embedded in the walls or ceiling of theroom.

ln general, the radiant heat panel of the' present invention comprises abacking plate having perforated or eX- panded portions capable ofserving as a metal lath. A continuous sinuous tube is secured to thebacking plate by suitable means, as by deformation of the plate or thetube, the tube serving to convey a heat transfer fluid closely adjacentthe plate so that the backing plate and tube together serve efhcientlyas a heat exchanger. The improved wall construction thus obtainedincludes the radiant heat panel and the coating of plaster appliedthereto.

To employ the radiant heat panel hereinbefore described, the heat panelis secured to the joists or studding or inner wall or ceilingconstruction of a room and plaster is applied directly over the entireradiant heat panel. The perforated or expanded backing plate serves toprovide an adequate anchoring base for the plaster applied to the panel,and the efficient heat transfer from the plastered wall upon thecirculation of heated fluid through the exchanger serves to heat theroom.

It is, therefore, an important object of the present invention toprovide an improved radiant heat panel.

Another important object of the present invention is to provide animproved wall construction including a radiant heat panel capable ofserving as a plaster base and as a heat exchanger, and a layer ofplaster applied to the heat panel.

A further important object of the present invention is to provide animproved radiant heat panel including a backing plate capable of servingboth as a plaster base and as a heat exchange member, and a sinuous tubesecured to the plate for conveying a heat exchange fluid in thermalproximity to the backing plate.

lt is a still further important object of the present invention toprovide an improved method for making a radiant heat panel,

On the drawings:

Figure 1 is an elevational view, with parts broken away,

showing the installation of the radiant heat panel of the presentinvention in a wall or the like;

Figure 2 is an enlarged, broken sectional view further illustrating theinstallation of Figure l;

Figure 3 is an enlarged, broken elevational View of the radiant heatpanel of the present invention;

Figure 4 is an enlarged, fragmentary sectional View illustrating onestep of the method of making the heat exchanger of the presentinvention;

Figure 5 is an enlarged sectional view similar to Figure 4 illustratinga further step in the manufacture of the radiant heating panel; l

Figure 6 is a perspective, fragmentary, somewhat schematic View of aroom equipped with radiant heat panels of the present invention andillustratingvthe circulation of a heat exchange medium through thepanels;

Figure 7 is an enlarged, broken elevational View illustrating a modifiedform of radiant heating panels of the present invention;

Figure 8 is an enlarged, fragmentary sectional view showing one step ofa modified method of making a radiant heat panel of the presentinvention; and

Figure 9 is an enlarged, fragmentary sectional View similar to Figure 8and showing another step of the method of Figure 8.

As shown on the drawings:

In Figure 1, reference numeral 10 refers generally to a radiant heatpanel of the present invention including a backing plate 11 formed of ametal sheet having desirable heat transfer properties. The backing plate11 is provided with longitudinal aligned, vertically ofset series ofrows of perforations 12 separated by spaced, non-perforated portions 13extending entirely across the width of the plate 11.

The plate is thus divided into a plurality of apertured sectionsseparated by non-apertured plate sections.

The non-apertured plate sections 13 of the plate 11 are adapted toreceive a sinuous tube 14 having straight, substantially parallelportions 14a joined by curved portions 14b. As may be seen from Figure3, the straight portions 14a of the sinuous tube 14 extend across theentire width of the plate 11 and the curved portions 14b lie outside ofthe confines of the plate 11. The straight portions 14a of the tube 14are preferably employed to join the tube to the plate to secure the samethereto against relative movement.

As shown in Figures 4 and 5 of the drawings, the preferred method forsecuring the tube 14 to the nonapertured portions 13 of plate 11involves irst the formation of a re-entrant groove 15 in thenon-apertured plate portion 13. The formation of the re-entrant groovemay be carried out by the employment of a iiexible, resilientlydeformable forming die, such as a die made of rubber, or by iirstforming a groove having an arcuate bottom and straight upstanding sidewalls with the side walls later being deformed outwardly to define thearcuate, re-entrant side walls of the grooves 15. By either method, there-entrant groove 15 thus formed is provided with a restricted grooveinlet 16 defined by arcuate groove side walls 15a and the arcuate groovebottom 15b. The tube 14 is positioned within the groove 1S and isbottomed against the arcuate bottom 15b of the groove. Next, one exposedportion of the tube 14 is deformed or fiattened, as at 17, so that thetube is deformed from its circular cross-section with the walls of thetube being collapsed outwardly against the interior surfaces of thearcuate side walls 15a of the groove 15 with the deformed tube being ingreater than semi-peripheral contact with the groove 15.

Alternatively, the tube 14 may be secured to the plate 11 by the methodshown in Figures 8 and 9 of the drawings. In the practice of thismodified method, the nonapertured portions 13 of the plate 11 areprovided with grooves 21 having relatively straight, upstanding sidewalls 22 and an arcuate, closed bottom wall 23. The grooved plate 11 isnext placed on a backing die 24 having an elongated groove 25 formedtherein to receive each of the grooves 23. It is to be noted that thegroove 23 is bottomed in the groove 25, while the plate portion 13 isspaced from the upper surface of die 24, as at 26. In addition, the sidewalls 22 of the plate groove 7.1 are spaced inwardly from the side walls27 of the die groove 25. The tube 14, or more particularly, the straightportions 14a of the tube 14, is bottomed in the groove, the arcuateinner periphery of the groove bottom wall 23 preferably snugly receivingthe tube 14a, as shown in Figure 8. Thus, preferably the outsidediameter of the tube 14a is approximately the inside diameter of thearcuate bottom groove wall 23.

The deformable, hollow tube 14a is next contacted with a forming punchor roll 2S urged against the tube 14 to deform the same, as at 29, tothe forni shown in Figure 9. The tube 14a, being hollow and deformable,thus serves to transmit force from the punch 28 to the side walls 22 ofthe groove 21. Since the groove wall 23 is bottomed in the groove 25,and further, since clearance is provided between groove side walls 22and 27, the groove side walls 22 are deformed outwardly into contactwith the side walls 27 of the die 24. The deformation of the tube 14aand the walls 22 increases the width of the groove 21, and this increasein width draws the plate 13 downwardly into extended surface engagementwith the upper exposed surface of die 2d. Also, the plate portions 13 ofthe plate 11 are each deformed to the contour of Figure 9simultaneously, so no un desired lateral or transverse movement of theplate 11 can occur. The resulting simultaneous deformation of the plateand the tube securely locks the tube to the plate and the finishedarticle is identical with that illustrated in Figure 5.

The tube 14, when made by either of the hereinbefore explained methods,is maintained in position within the groove by the re-entrant contour ofthe plate groove, the restricted groove inlet 16 and the non-circularcontour of the tube. in particular, the tube is maintained in positionwithin the groove by the engagement of the tube with the interior sidewall surfaces of the arcuate side walls 15:1 at a point below therestricted groove inlet 16. Thus, it may be seen that the tube isreadily secured to the grooved non-apertured plate portions 13.

In the modification of the invention shown in Figure 7 of the drawings,the backing plate takes the form of an expanded metal lath section 18with the apertured portions 13 of the plate 11 being formed as anexpanded metal sheet of conventional type separated by nonexpandedintermediate portions 19 similar to the portions 13 hereinbeforedescribed. A sinuous tube 14 is secured in the manner hereinbeforedescribed within a re-entrant groove extending across the entire widthof the backing plate 18. The curved portions 14h of the tube 14- alsoextend beyond the expanded sections 18 of the plate.

It will, of course, be understood that each of the forms of backingplates may be provided by joining non-apertured portions 13 ornon-expanded portions 19 to expanded or apertured metal lath sections.Alternatively, the expanded metal laths or apertured metal lath backingsheets may be formed with integral non-apertured orv non-expandedportions to receive the straight portions 14a of the tube 14. In eachcase, the tube 14 is secured to the non-apertured or non-expandedportions of the plate by means of the re-entrant groove and distortionof the tube as hereinbefore described.

The employment of the radiant heating panel of the present invention isillustrated in Figures l and 2 of the drawings, in which it may be seenthat the radiant heat panel is secured to the wall or ceiling supportingstructure, as to the joists or studding, by suitable means, as

by nails or the like (not shown), and that a layer of plaster 20 islater applied directly to the radiant heat panel. The heat panel ispreferably installed with the grooves of the panel extending outwardlyof the finished wall surface 20h toward the supporting wall structure.

It will be seen in Figure 2 that plaster indicated generally at 20 williiow through the apertures 12 of the aperture portions of the radiantheat panel 10 and that this plaster will form a substantially continuouslayer 20a on each side of the radiant heat panel, inasmuch as thatplaster passing through the apertures 12 is separated by only arelatively narrow non-apertured plate portion lying between theapertures 12.

The outer finished plaster surface 20b then may be finished by theconventional practices of the art with the radiant heat panel 10 beingcompletely embedded in the finished wall. It is obvious that upon thepassage of heat exchange iiuids through the tube 14 that this heat willbe imparted to the backing plate for heating the interior of the room inthe walls in which the heat exchanger 10 is embedded.

However, it is preferred that the entire wall or ceiling panel orstructure be pre-fabricated as a single structural unit. By Way ofexample, the metal lath and tube assembly 10 may be molded into plasterin predetermined lengths and widths with the inner plaster wall faceiinished smooth to present a desirable, smooth surface. Alternatively,or in addition, the wall structure may be finished with a paper orfibrous sheet or with a fabric covering material. The joints betweensuch prefabricated panels may be joined and sealed by the use of joiningtape or moulding. By the use of such prefabricated structures,plastering at the site could be eliminated and only painting would benecessary to provide a nished Wall surface.

In Figure 6 is illustrated a residential heating system, shown somewhatdiagrammatically as employed in a room 30, heated by radiant heat panels10 of the present invention. The room 30 may be heated by any desirableform of conventional boiler or furnace 31 capable of heating a heattransfer medium to a relatively elevated temperature. The heat transfermedium is circulated through an upwardly extending pipe or line 31 intoa header pipe or line 32 adjacent the ceiling of the room. The headerpipe 32 is connected, as at 33, to the free end of a tube 14 of aradiant heat panel 10 as hereinbefore described, The heat transfer uidis thus introduced from the header pipe 32 into the line 14 of the heatpanel 10 and following its passage through the heat panel is nextintroduced into a return line 35 connected as at 34 to the other freeextremity of the tube 14 of the radiant panel 10. The return line 35extends downwardly along one wall of the room and parallel to line 31into communication with a suitable pump 36 for maintaining operatingpressures in the line throughout the system as hereinbcfore described.Fluid from the pump 36 is returned to the boiler 31 through return line37.

It will be noted that a number of heat panels 10 are illustrated asdisposed within the ceiling of the room 30, the number of heat panels 10depending upon the size and heating characteristics of the room. It isto be noted that those panels 10 which are transversely aligned are indirect abutment while those panels in longitudinal alignment havedisposed therebetween a strip 39 of perfo rated or expanded metal lathcontaining no tubes 14. In this manner, any installation diiculties dueto the size and contour of the panels 10 are avoided.

The number of heating installation variations which are possible will beappreciated and the wide applicability of the radiant heat panels of thepresent invention will be evident. In addition to those panels 10disposed in the ceiling of the room 30, an additional panel 10 isprovided within one wall directly under a window 38. It has been foundthat, although a ceiling installation such as that herein described isgenerally sufficient to heat a toorn', it might be desirable to providean additional panel adjacent windows, doors or other structuralcomponents of the room through which serious heat loss might occur. Thepanel 10 disposed beneath the window 38 is disposed in series with thepanels 10 of the ceiling with the window panel being connected to theuid lines 31 and 35 hereinbefore described.

It will, of course, be understood that various details of constructionmay be varied through a wide range without departing from the principlesof this invention, and it is, therefore, not the purpose to limit thepatent granted hereon otherwise than necessitated by the scope of theappended claim.

I claim as my invention:

'I'he method of forming a heat exchanger which includes the steps offorming a groove in a sheet metal backing plate having asemi-cylindrical bottom wall and straight upstanding side walls,positioning a continuous circular cross-section tube of externaldiameter substantially equal to the internal diameter of saidsemi-cylindrical wall in said plate groove, placing the backing plate ona die structure having a groove for receiving the backing plate groove,said die groove being slightly Wider than the overall width of the plategroove and slightly shallower than the overall projection of the plategroove from the plate, and applying a reshaping force through the mouthof said groove against said tube to press the side walls of the tubeagainst the side walls of said plate groove, and continuing to exert areshaping pressure against said tube to force the side walls of the tubeto press the side walls of the plate groove outwardly from straightupstanding relation while leaving a re-entrant configuration with theside walls of the plate groove overlying lthe top part of the tube andlocking the tube in the plate groove.

References Cited in the file of this patent UNITED STATES PATENTS1,971,723 ODell Aug. 28, 1934 1,982,075 Smith Nov. 27, 1934 2,050,993Bush Aug. 11, 1936 2,091,584 Brown Aug. 31, 1937 2,092,170 Kritzer et alSept. 7, 1937 2,268,885 McCullough Ian. 6, 1942 2,281,299 SteenstrupApr. 28, 1942 2,338,090 Bradiield Ian. 4, 1944 2,441,463 Achs May 11,1948 2,548,036 Milborn Apr. 10, 1951 2,585,043 Sandberg Feb. 12, 19522,666,981 Sandberg Jan. 26, 1954 FOREIGN PATENTS 260,414 Great BritainNov. 4, 1926 307,219 Great Britain Mar. 7, 1929 879,224 France Nov. 10,1942 891,592 France Mar. 10, 1944

